The chief executive of US biotech company Illumina has accused US regulators of “time-wasting manoeuvrings” in its scrutiny of the group’s $8bn acquisition of Grail, the cancer screening start-up backed by Jeff Bezos and Bill Gates.

Francis deSouza’s comments come after a US judge ruled in favour of a petition by the Federal Trade Commission to cancel its action seeking to block the deal while Brussels investigates it.

The court ruling also allows the FTC to bring a case to block the acquisition in the future, giving the watchdog even more leeway to use the process to stall the deal, deSouza said.

US regulators filed a motion to block the transaction in March and since then Brussels has also announced a probe, despite a legal challenge arguing that it has no formal jurisdiction over the case since Grail posts no revenues in Europe.

DeSouza told the Financial Times: “The biggest challenge is getting the FTC to move with the appropriate sense of urgency and getting the FTC to stop the time-wasting manoeuvrings and just focus on the case and get this case to trial.”

Last Friday a San Diego judge heard arguments from US regulators to dismiss part of their case against the merger because of a probe now moving through Brussels.

DeSouza added: “My ask has to be: don’t pause. The FTC is asking to stop working on this case now and wait to see what happens over the next few months in Europe.”

He warned that lives were at risk if the deal was stalled further. “There are a lot of people who depend on this case. Do the homework, make your case, let’s go to court, and let’s get a decision. Stopping is the wrong answer for millions of people around the world.”

The FTC declined to comment but pointed to an earlier release outlining its argument for dismissing the case as EU regulators announced an investigation into the deal.

Illumina is the market leader for sequencing genomes, with $3.2bn in revenues last year, and provides machines to researchers for clinical prenatal tests and more recently to labs seeking to identify new Covid-19 variants.

Grail, which was founded by Illumina in 2016, develops a new type of cancer screening test with the ability to detect more cancers earlier and with better results.

Illumina is suing the European Commission, arguing that regulators in Brussels have no jurisdiction over the transaction. Lawyers representing Illumina say the EU probe is likely to cause delays in completing the deal, which must close by December 20. The company said it was nevertheless “co-operating”.

“We’re pursuing the deal in the EU,” said deSouza. “We believe this deal is pro-competitive and good for patients.

“Cancer patients deserve a regulatory process that puts people over process manoeuvrings.”